1. Field of the Invention
This invention is directed to novel compounds comprising adducts of alkyl or aryl phosphorodithioic acids and a sulfurized olefin.
2. Summary of the Prior Art
Sulfurized olefins are known to be effective extreme pressure agents or load carrying additives for lubricating oils; U.S. Pat. Nos. 3,703,504; 3,697,499 and 3,471,404.
Phosphorodithioic acids have been reacted with olefins; see for example, U.S. Pat. Nos. 3,646,172 and 3,350,348, and A. A. Oswald, Journal Organic Chemistry, 27, 2439 (1962). However, none of these processes are similar to the instant process nor are the compounds so produced similar to the novel adducts of this invention.
It has now been discovered that when a dialkyl or diaryl phosphorodithioic acid is added in low concentration to the unsaturated components of certain sulfurized olefins low phosphorus (0.1-10%), high sulfur (ca. 25% or more) content products result. These products have improved oil solubility and odor as compared to the sulfurized olefin and impart good antiwear and antioxidant activity, and good copper corrosivity to organic substrates, e.g., lubricating oils, when incorporated therein.